Description - Tech Controllers EU-880 zPlD User Manual

EU-880 zPID
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Description

The EU-880zPID temperature controller is designed for use with central heating boilers. It controls the
following units: central heating (CH) water circuit pump, domestic hot water (DHW) pump, circulating or
valve pump, mixing valve and fan. Optionally, control functions can be also provided for two additional
mixing valves via ST-61 modules.
The ST-880zPID controller is a unit with a continuous output signal using a modified PID control
algorithm. In this type of controller the blowing power is calculated by measuring the boiler temperature
and the flue gas temperature as measured at the outlet of the boiler. The fan is run continuously and the
blowing power depends directly on the measured temperature of the boiler, the flue gas temperature and
the difference between these parameters and their set-points. The advantages of a modified PID
controller include the ability to maintain a stable set-point temperature without any unnecessary
overshoot or oscillations.
When using this type of controller equipped with a flue gas outlet sensor fuel savings can be
achieved from a few percent up to around 15 percent with the output water temperature kept at a very
stable label, resulting in longer life of the exchanger (boiler). As the flue gas temperature at the boiler
outlet is controlled this results in low emissions of dust and gases that are harmful to the environment.
The thermal energy of the flue gas is not wasted and released into the chimney, but is instead used for
heating.
Below we present the results of tests conducted with the use of the Tech controller with PID control:
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